URIteacherknowledge - scd720fluidspheres'08Coriolislabsteps

STEP 1: Your goal is to create a manually-spinning disc, (like a spinning top or a record) with a flat surface with the materials provided. Each person should create their own spinning disc.
STEP 2. Once the spinning disc is created, spin it between your fingers on a flat surface to ensure it has good rotation. Assign somone as the designated disc spinner.
STEP 3. Have another group member hold a ruler about 2 or 3 inches above the disc, parallel to the ground, to create a straight edge just as if someone was using the ruler to draw a straight line on the disc. This will guide the tracer's movement.
STEP 4. Now, while the group member is holding the ruler in a steady position and while the other is holding the disc stationary, have a remaining group member trace a straight line (using the ruler as a guide) onto the disc. Once your make your line, put an arrow on the end to show the direction your line was travelling.
- Trace two more "arrows" using the ruler, onto the disc as follows...
  - once (in green) while the disc spinner steadily rotates the disc counterclockwise
  - once (in purple) while the disc spinner steadily rotates the disc clockwise
STEP 5: Carefully observe the path of the different colored arrows. Record whether your line came out straight or curved. If it was curved, indicate the disc rotation and if it curved to the right or to the left. (Do Not Use Counterclockwise/Clockwise to indicate the movement of the line. It will only confuse you.)
STEP 6: Repeat STEPS 3 through 5 until each group member's disc is marked with the three different colored lines.
STEP 7: As a group, sum up what happened to each of the three lines in a table below:

disc movement	color of line	shape of line	curvature
stationary
counterclockwise
clockwise

STEP 8: Answer the following: Even though you drew the marker in a straight line each time, it created a curved path. Why?
STEP 9: Discuss with your group which way you think the earth rotates: Clockwise or counterclockwise. Does it depend on your location?